Method and apparatus for annealing sheet glass



J. 1.. DRAKE Feb. 25, 1930.

METHOD AND APPARATUS FOR ANNEALING SHEET GLASS Filed May 19. 1927 gmue'ntoi Job/2 LD/a/(e U MEG.

6 131301 nag Patented Feb. 25, 1930 means i .EE

JOHN L. DRAKE, OF TOLEDO, OHIO, ASSIGNOR TO LIBIBEY-OWENS GLASS COMPANY, OF TOLEDO, OHIO, A CORPORATION OF OHIO METHOD AND APPARATUS FOR ANNEALING SHEET GLASS Application filed May 19, 1927. Serial No. 192,513.

This invention relates to an improved niethod and apparatus for annealing sheet g ass.

In the annealing of sheet glass such as for example in the Colburn process, the highl heated sheet is passed horizontally throng an' annealing oven or leer wherein it is annealed to remove strains and then gradually reduced to room temperature. In order to prevent a too rapid escape of the heat from the sheet which would result in a too rapid cooling thereof, additional means, usually in the form of gas burners, are placed at spaced points within the leer longitudinally thereof whereby to maintain a constantly heated at mosphere around the sheet at all times. The temperature of this atmosphere gradually diminishes longitudinally of the leer. Also, in certain types of leers, the sheet is exposed to atmospheric ehanges which are very apt to aifect the same, proving detrimental to the proper annealing thereof. When the sheet enters the leer, it passes through what is termed a critical stage or range wherein the annealing must be accurately controlled to prevent a too rapid or ununiform coollng thereof. After the sheet passes through this critical range, however, it can be cooled much more rapidly provided, of course, that it IS cooled uniformly. 7

It is an aim of the present invention to provide an improved method and apparatus for annealing sheet glass wherein a relatively slow, uniform annealing of the sheet can be accomplished.

Another object of the inventionis to provide improved means for maintaining a constantly heated medium around the sheet.

whereby to prevent a too rapid cooling thereof.

A further object of the invention is to provide in apparatus for annealing sheet glass, insulating means surrounding the sheet within the leer for effecting a slow, uniform operation to the end that extraneous heating means can be eliminated and the sheet annealed by its own heat.

Other objects and advantages .of the invention will become more apparent during the course of the following description when taken in connection wth the accompanying drawings.

- In the drawings forming a part of this application and wherein like numerals are employed to designate like parts throughout the same,

Fig. 1 is a longitudinal vertical section through the improved annealing apparatus provided by the present invention.

Fig. 2 is a transverse section through the same.

3 is a top plan view, and

Fig. 4 is a detail end view of Fig. 3.

Referring to the drawin s in detail, the numeral 5 refers to a charm er in which the sheet of glass 6 is continuously drawn and flattened in a manner more fully disclosed in the patent to Colburn No. 1,248,809, granted Dec. 4, 1917.

Arranged in front of and attached to the chamber 5 in horizontal alignment with the sheet as it passes therefrom, is an annealing oven onleer 7 of suitable size for annealing the sheet. The sheet is preferably advanced through the leer upon and by a plurality of driven leer rolls 8 or other form of supporting means. There are openings 9 provided in the side walls of the leer for either removing or replacing the rolls 8,- and arranged within these openings are bearing members 10 for supporting the opposite ends of the shafts 11 carrying the rolls 8. Each bearing member 10 is provided at its inner end with an inturned flange 12 and mounted upon the shaft 11 within the bearing member and immediately adjacent this flange is a collar or sleeve 13. The advantages of such an arrangement will be more clearly hereinafter apparent. Positioned above the leer and communicating therewith through the top thereof adjacent the chamber 5 is a hopper 14 within which is arranged an agitator 15.

Positioned beneath the rolls 8 and extending longitudinally within the leer is an endless belt conveyor 16 trained about drums 17. 95 This endless belt conveyor may be of any de sired length and the upper run thereof is supported upon a plurality of rails 18 while the lower run is prevented from sagging and held in a taut condition by an idler roll 19.

Positioned adjacent the outer end of the endless belt conveyor 16 is a second endless belt conveyor 20 which is arranged transversely within the leer and extends outwardly through openings in the side walls thereof. This belt is trained about pulleys or spools 21 carried by shafts 22 and the upper run thereof is supported within the leer upon a supporting member 23, the top plate 24 of which is substantially V-shaped in cross section as shown in Fig. 1.

In carrying out the present mvention, any suitable insulating material in powder form and generally indicated by the numeral 25,

is adapted to be introduced into the hopper 14. This insulating material being in a powdered form gravitates through the ho per.

onto the moving sheet 6 and is carried a ong upon the same. A portion of this material will naturally fall down upon the endless conveyor belt 16 around the ends of the TOllS 8 as shown in Fig. 2 and the flanges 12 and collars or sleeves 13 above described are provided for preventing any of this material from finding its way into the bearing members 10. I

A quantity of this insulating material sufficient to fill the entirespace above the sheet at all times is adapted to be fed through the hopper 14 but' it will be evident that the amount of material falling down around the ends of the rolls 8 will not be suflicient to fill the entire space between the sheet and the material to be removed from the endless belt 26 and deposited onto the conveyor belt 16 which will carry it longitudinally through the leer. The upper run of this belt 26 is supported upon and conforms to a transversely ent plate 29 so formed that the insulating material 25 will be prevented from falling 01f of the side thereof adjacent the chamber 5.

The sheet 6 is adapted to carry the insulating material above the same while the conveyor belt 16 is adapted to carry the material beneath the sheet. At the end of the conveyor belt 16, the material is dumped onto the conveyor belt 22 and carried exteriorly of the leer where it is deposited into a plurality of buckets or cups 30 carried by the endless conveyor 31. This conveyor is inclined so that it will convey the material back to and deposit it within the hopper 14. In this manner, the same insulating material can be used over and over again. A scraper 32 positioned above the sheet at the outer end of the conveyorbelt 16 is provided for preventing means further passage of the insulating material might prove detrimental thereto, it will permit a relatively slow uniform cooling thereof in order to accomplish the relatively slow, uniform annealing action. As stated, the insulating material incloses the sheet throughout the entire critical range of the annealing operation and due to the medium used no extraneous heating devices are necessary or desirable. After the sheet passes beyond the critical stage, it can be cooled much more rapidly without danger and in order to accomplish, this, if preferred, positive cooling means in the form of coolers 34 may be arranged within the leer and in proximity to the sheet.

It is to be understood that the form of the invention herewith shown and described is to be taken as the preferred embodiment of the same, and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

Claims:

1. In apparatus for annealing sheet glass, at leer for receiving a moving sheet to be annealed, and substantially solid means surrounding the moving sheet and contacting therewith within the leer for preventing a too rapid cooling thereof.

2. In apparatus for annealing sheet glass, a leer for receiving a moving sheet to be annealed, and a owdered material surrounding the moving s eet and contacting therewith within the leer for preventing a too rapid dissipation of the heat therefrom.

3. In apparatus for annealing sheet glass, a leer'for receiving a moving sheet to be annealed, and a movable body surrounding the moving sheet within the leer to prevent a too rapid cooling thereof. v

4. In apparatus for annealing sheet glass, a leer for receiving a moving sheet to be annealed, and a movable body of substantially solid material surrounding the moving sheet roe within the leer to prevent a too rapid cooling I 5. In apparatus for annealing sheet glass, a leer for receiving a moving sheet to be an nealed, and a movable body of insulating material surrounding the moving sheet within the leer. p

6. In apparatus for annealing sheet glass, a leer for receiving a moving sheet to be annealed, a powdered insulating surrounding the sheet withinthe leer, means for introducing said mater1al into the leer,

and means for conveying it exteriorly of said t I leer. v

7. In apparatus for annealing sheet glass, a leerfor receiving a moving sheet to be an! nealed, means for introducing a supply of powdered'insulating material into the leer carrying said material throu h the leer,

means for receivin the materlal from the carrying means an conveying it exteriorly of the leer, and means for returning the material to the introducing means. I 8. In apparatus for annealing sh a' leer for receiving a moving sheet to be annealed, means'for introducing a supply of powdered insulating material within the leer above the sheet, means for introducing the material beneath the sheet, means for carrying the material longitudinally within the leer, means for receiving the material and conveying it exteriorly of the leer, and means .ing means."

no means.

" '9. The method of annealing sheet 'glass which consists in passing the sheet through and in contact with substantially solid 10. The method of annealin sheet glass which consistsin-passing the s eet through and in contactv with a body of insulating material.

which consists in passing the s eet through a movable body of powdered insulating material.

12. The method of annealing sheet glass which consists in substantially enclosing a continuously movin sheet in-a body of insulating material w ich contacts therewith.

v 13. The method of annealing sheet glass 'which consists in substantially enclosing a continuouslyn moving sheet in a body of powdered insulating material which con tacts therewith. I

14. The method of annealing sheet glass which consists in passing the sheet horizontally through an annealing leer, and simultaneously passing through said leer a powdered insulatin neath said sheet.

Si ed at Toledo, in the county of Lucas and tate of Ohio, this 17th ,dayof May, 1927.

JOHN L. DRAKE.

and in contact with the sheet, means for eetv glass, I

for returning the material to the introduc- 11. The method of annealin sheet glass g material above and be- 

